8 31 12 eukaryotes prokaryotes viruses 17th century Percivall Pott MD Diseases linked to certain occupations British Neurological disorders with workers in paint Cancer of scrotum of younger men Scrotum houses testicles Connection drawn with men working as chimney sweeps Chimney sweeps usually were children as they were smaller and could fit into the chimneys Soot Linked agent soot to form of cancer FIRST TIME LINK MADE lesion manifested itself 10 years after exposure some sort of memory to cells soot hydrocarbon causes mutation of proliferating cells Pott s Disease circulation disorder in extremities Pott s fracture Hippocrates Galen 466 BC in Greece Keep records observations established medicine practices Prognostication physical changes that alter health of individual not mystical cause What humans and animals consist of 4 humors Blood phlegm yellow bile black bile the imbalance of these humors that cause someone to become ill Continues to influence medicine today Microscopes Light Microscope larger organelles Tissues Electron organelles Scanning tunneling look at structure of atom Robert Hooke focusing light on top of object Cork saw formerly living cells Remnants of cellulose in cell walls 1665 published book with drawings from microscope observations Van Leeuwenhoek 17th century textile merchant observant on density of weaves 150 microscopes metal plate with hole place close to eye and look through lens member of Royal Society of London first to describe RBCs ejaculate from animals and described protozoa Cell Theory Robert Brown 1800s plant tissue with staining and microscope Saw opaque spots called them nuclei Matthias Schleiden 1838 Theodor Schwann 1839 developed cell theory Nuclei associated with structures that are compartment like Secretory cells nuclei away from ducts 1 opaque spots nuclei with compartments Each compartment holds nucleus 2 living organisms consist of cells Each cell is an independent entity looking under light microscopy able to see nucleus and some organelles no mitochondria Can t see membrane can see distinction between composition of cytoplasm and membrane Developing cell theory came from 15 years later from Rudolph Verchow who suggested all cells originated from other cells and not from spontaneous generation Emphasized Level of detail from light microscopy is limited Eukaryotic vs prokaryotic Plant Cell Wall Paramecium swim Experiment traced cilia movement Does the voltage across membrane when animals bump into object Prokaryotes Dimension of cylinder 5 micrometers to 2 Plasma membrane Capsule cell wall like keeps membrane from exploding Some have flagella not flexible like cilia More like corkscrew work by movement of ship Flagellum rotate in one direction NO NUCLEI DNA found in 1 circular chromosome found in region of cell called nucleoid Human DNA length 2 meters of DNA Bacteria 1 5 mm DNA must be replicated about 300 genes selectively expressed Must alter specific genes to be expressed After digesting cell wall 1 chromosome bursts out Eukaryotes 20 30 micrometers nucleus 8 micrometers Lecture 2 9 5 12 genes selectively expressed dependent on condition of cell chromosome is 1000th the dimension of a cell packed as a result of structural proteins and RNA capsule around cell envelope between plasma membrane and envelope things diffuse through gram negative positive staining as a result of the envelope Gram positive stain through wall and cytoplasm Gram negative doesn t stain that well Describes elaboration of membrane lipids in outer membrane sometimes trigger immune response to gram negative cells SOS response to immune infection with GRAM NEGATIVE if plasma membrane and envelope rupture causing chromosome to unfold Bacteria problems 2 kilos of bacteria 3 lbs per person Most in intestines Cholera bacillus Responsible for releasing toxin causes diarrhea and other Ehrlichia affect monocytes found in blood migrate to sites of infection perform phagocytosis lonestar tick bites Phagocytic vesicles carries bacteria ingested via phagocytosis Buds with vesicles Digested particle usually degrades Vesicle fuses to lysosomal enzymes for digestion lysosome with 20 30 types of enzymes for digestion Can digest nucleotides carbohydrates everything except each other and the organelle Only requirement of lysosome is to function at pH 4 5 5 0 within lysosome more protons than OH s requires energy ATP to keep at this pH why not make pH higher to save energy In case membrane ruptures protects itself from cell The hydrolytic enzymes released would not damage the cell gram negative blocking event of vesicle fusing to lysosome Infection continues to spread ehrlicihia unprotected Begin to proliferate inside phagocytic compartments Then able to be dumped and infect other cells unless immune compromised antibiotics are able to help escaping body s immune response Thiomargarita namibiensis sulphur pearl of Namibia Use H2S accumulate sulfur to accumulate pearl appearances Very large Visible to naked eye Viruses Peyton Rous 1911 for the muscle tissue Fibrosarcoma resulted from a biological substance won nobel prize first RNA virus caused cancer sarcoma connective tissue tumors in fibroblasts that proliferate Responsible studied chicken with lumps study removed sarcoma tissue Grinded in solution Passed through Buchner with a number of filters Pores of filter too small for bacteria to pass Filtrate injected into young chicken Observed lumps again Conclusion lumps are cancer Caused by infectious agent Agent developed to be virus Genome made of RNA Not visible under microscope With introduction of electron microscope able to identify Virus life cycle envelope not living Require living organism to multiply Genome made of DNA or RNA Complexed with proteins or lipids for bacteriophage genome in head Neck and tail regions Infects bacteria Spike like legs that bind to surface of bacterium Penetrate through membrane and cell wall Bind to proteins on cell membrane that are responsible for moving sugars into cell Porins channels through envelope which sugars move into cell and DNA from bacteriophage is then inserted Once penetrated and DNA is inserted viral DNA becomes part of host chromosomes and with replication viral genome is replicated with it LYSOGENIC CYCLE if cell faces extreme conditions production of virus turns on goes through lytic phase and produce viral particles that are shedded by cell and infect other cells Figure 7 67 shows steps of infection Lysogenic cycle lytic
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